Configuring spanning elements of a signature generator

ABSTRACT

Systems, and method and computer readable media that store instructions for configuring spanning elements of a signature generator.

CROSS REFERENCE

This application claims priority from U.S. provisional patent 62/827,117filing date Apr. 1, 2020 which is incorporated herein by reference.

This application claims priority from U.S. provisional patent 61/827,112filing date Mar. 31, 2019 which is incorporated herein by reference.

BACKGROUND

Object detection has extensive usage in variety of applications,starting from security, sport events, automatic vehicles, and the like.

Vast amounts of media units are processed during object detection andtheir processing may require vast amounts of computational resources andmemory resources.

There is a growing need to provide an efficient object detection method.

SUMMARY

There may be provided systems, methods and computer readable medium asillustrated in the specification.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of the disclosure will be understood and appreciatedmore fully from the following detailed description, taken in conjunctionwith the drawings in which:

FIG. 1 illustrates an example of a first dictionary;

FIG. 2 illustrates an example of a second dictionary;

FIG. 3 is an example of an image;

FIGS. 4 and 5 illustrate various original patches, sparserepresentations and reconstructed signal representing the originalpatches;

FIG. 6 is an example of a histogram;

FIG. 7 illustrates an example of augmented image;

FIG. 8 is an example of a graph that illustrates a frequency ofappearance of various features in an image;

FIGS. 9 and 10 illustrate an example of an image and reconstructedimages;

FIG. 11 illustrates an example of an image that includes groups ofpatches, an original image and a reconstructed image;

FIG. 12 illustrates an example of an image that includes groups ofpatches, an original image and a reconstructed image;

FIG. 13 illustrates an example of images;

FIG. 14 illustrates an example of a method;

FIG. 15 illustrates an example of a signature;

FIG. 16 illustrates an example of a dimension expansion process;

FIG. 17 illustrates an example of a clusters of a signatures matchingprocess;

FIG. 18 illustrates a method;

FIG. 19 illustrates a method; and

FIG. 20 illustrates a system.

DESCRIPTION OF EXAMPLE EMBODIMENTS

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of the invention.However, it will be understood by those skilled in the art that thepresent invention may be practiced without these specific details. Inother instances, well-known methods, procedures, and components have notbeen described in detail so as not to obscure the present invention.

The subject matter regarded as the invention is particularly pointed outand distinctly claimed in the concluding portion of the specification.The invention, however, both as to organization and method of operation,together with objects, features, and advantages thereof, may best beunderstood by reference to the following detailed description when readwith the accompanying drawings.

It will be appreciated that for simplicity and clarity of illustration,elements shown in the figures have not necessarily been drawn to scale.For example, the dimensions of some of the elements may be exaggeratedrelative to other elements for clarity. Further, where consideredappropriate, reference numerals may be repeated among the figures toindicate corresponding or analogous elements.

Because the illustrated embodiments of the present invention may for themost part, be implemented using electronic components and circuits knownto those skilled in the art, details will not be explained in anygreater extent than that considered necessary as illustrated above, forthe understanding and appreciation of the underlying concepts of thepresent invention and in order not to obfuscate or distract from theteachings of the present invention.

Any reference in the specification to a method should be applied mutatismutandis to a device or system capable of executing the method and/or toa non-transitory computer readable medium that stores instructions forexecuting the method.

Any reference in the specification to a system or device should beapplied mutatis mutandis to a method that may be executed by the system,and/or may be applied mutatis mutandis to non-transitory computerreadable medium that stores instructions executable by the system.

Any reference in the specification to a non-transitory computer readablemedium should be applied mutatis mutandis to a device or system capableof executing instructions stored in the non-transitory computer readablemedium and/or may be applied mutatis mutandis to a method for executingthe instructions.

Any combination of any module or unit listed in any of the figures, anypart of the specification and/or any claims may be provided.

The specification and/or drawings may refer to an image. An image is anexample of a media unit. Any reference to an image may be appliedmutatis mutandis to a media unit. A media unit may be an example ofsensed information. Any reference to a media unit may be applied mutatismutandis to any type of natural signal such as but not limited to signalgenerated by nature, signal representing human behavior, signalrepresenting operations related to the stock market, a medical signal,financial series, geodetic signals, geophysical, chemical, molecular,textual and numerical signals, time series, and the like. Any referenceto a media unit may be applied mutatis mutandis to sensed information.The sensed information may be of any kind and may be sensed by any typeof sensors—such as a visual light camera, an audio sensor, a sensor thatmay sense infrared, radar imagery, ultrasound, electro-optics,radiography, LIDAR (light detection and ranging), etc. The sensing mayinclude generating samples (for example, pixel, audio signals) thatrepresent the signal that was transmitted, or otherwise reach thesensor.

The specification and/or drawings may refer to a spanning element. Aspanning element may be implemented in software or hardware. Differentspanning element of a certain iteration are configured to applydifferent mathematical functions on the input they receive. Non-limitingexamples of the mathematical functions include filtering, although otherfunctions may be applied.

The specification and/or drawings may refer to a concept structure. Aconcept structure may include one or more clusters. Each cluster mayinclude signatures and related metadata. Each reference to one or moreclusters may be applicable to a reference to a concept structure.

The specification and/or drawings may refer to a processor. Theprocessor may be a processing circuitry. The processing circuitry may beimplemented as a central processing unit (CPU), and/or one or more otherintegrated circuits such as application-specific integrated circuits(ASICs), field programmable gate arrays (FPGAs), full-custom integratedcircuits, etc., or a combination of such integrated circuits.

Any combination of any steps of any method illustrated in thespecification and/or drawings may be provided.

Any combination of any subject matter of any of claims may be provided.

Any combinations of systems, units, components, processors, sensors,illustrated in the specification and/or drawings may be provided.

Any reference to an object may be applicable to a pattern.Accordingly—any reference to object detection is applicable mutatismutandis to a pattern detection.

Sparse Decomposition of Images Via Unsupervised Dictionary Learning

You only look once (YOLO) is a highly popular object detection methodand has multiple variants.

It has been found that YOLO and convolutional neural network basedobject detection provide object features that are heavily skewed towardsthe object types that they are trained on and do not give enoughdistinguishing power to patterns outside the labelled set.

Furthermore, the representation given by the higher layers of YOLO-typenetworks contain numerical values, both high and low, that are relatedto the object dimensions; picking only the highest features causessignificant information loss.

Finally, convolutional CNNs filters do not give clear intuition of whatthe features at each layer look like and it is not straightforward toreconstruct the data given just activation patterns in a specific layer.

Sparse representation of image features based on dictionary learning analternative that might help overcome these shortcomings.

Given a set of training signals {x₁, x₂, . . . x_(n)}, where x_(i)represents a patch of dimension m=h_(p)·w_(p)·c_(p), the method attemptsto find a dictionary D of dimension m by L, L being the number ofdictionary entries, such that for each x_(i), there exists a sparserepresentation α_(i) such that the number of non-zero entries in α_(i),i.e., |α_(i)|₀<<L, while Dα_(i) reconstructs each x_(i) with highfidelity.

Algorithmically, this is equivalent to solving the followingoptimization problem:

$\min\frac{1}{n}{\sum\limits_{i = 1}^{n}{{{D\;\alpha_{i}} - x_{i}}}_{2}^{2}}$

Such that |α_(i)|<λ for all i

Wherein λ is a constraint that can be set by a user—for example —maximumfive or ten per patch.

Efficient algorithms exist for performing stochastic gradient descentalternately on D and α, while convergence guarantees.

For example—there are shown examples of dictionaries learnt from variousimages.

Each one of FIGS. 1 and 2 illustrates dictionary learnt from sixty fourtraining images [each training image is a Continental 1024×640 pixels,RGB] in one of the following settings:

FIG. 1—dictionary 9501—h_(p)=w_(p)=16, L=1024FIG. 2—dictionary 9502—h_(p)=w_(p)=32, L=4096

Wherein h_(p) is the height of the patch and w_(p) is the width of thepatch.

Sparse Feature Decomposition

Once a dictionary D is learned, it can be applied to new image patchesto produce their respective sparse representation {α_(i)}. The sameoptimisation problem as before is solved while keeping D fixed. For thefollowing example image 9503 (included in FIG. 3), the method appliedthe first dictionary with 1024 entries and patch dimension 16·16·3.

FIGS. 4 and 5 illustrate various original patches (9504(1), 9504(2) and9504(3)) from image 9503, their sparse representation using D (9505(1),9505(2) and 9505(3)) as well as the reconstructed signal (9506(1),9506(2) and 9506(3)) representing the original patch.

The patches form a grid of patches and the location of each one ofpatches 9504(1), 9504(2) and 9504(3) is denoted by their row and column.First patch 9504(1) is denoted (15,15)—and is located at the 15'th rowand the 15'th column in the grid of patches.

Second patch 9504(2) is denoted (15,45)—and is located at the 15'th rowand the 45'th column in the grid of patches.

Third patch 9504(3) is denoted (25,5)—and is located at the 25'th rowand the 5'th column in the grid of patches.

Fourth patch 9504(4) is denoted (35,45)—and is located at the 35'th rowand the 45'th column in the grid of patches.

The sparse representation using D are illustrated by graphs or ratherhistograms that illustrate the amplitude of each dictionary element inthe sparse representation. Most dictionary elements are zero.

FIG. 6 is an example of a histogram formed for image 9503. The y-axis ifthe number of patches and the x-axis is the number of active features(nonzero dictionary elements) per patch.

The histogram shows that in relation to image 9503 the majority of thepatches can be represented by dozens of active features. In total,sparse decomposition yields 96608 non-zero entries, which translates toan average of about 38 active features per patch.

FIG. 7 illustrates an example of augmented image 9508 in which thenumber of active features (non-zero elements) per patch are overlaid onimage 9503. This shows that various textures in the image requiresdifferent number of features to represent.

FIG. 8 is an example of a graph 9509 that illustrates the frequency ofappearance of various features in image 9503.

Image Reconstruction

One advantage of the dictionary learning method is that back-forwardreconstruction is as simple as a single instance of matrixmultiplication, while CNN activations generally require some kind ofnon-linear optimization to traceback the input from the previous layer.

FIGS. 9 and 10 illustrates image 9503 and first, second, third, fourthand fifth reconstructed images 9511, 9512, 9513, 9514 and 9515respectively.

The first till fifth reconstructed images differ from each other by themaximal number of features that may represent each patch.

In first reconstructed image 9511 the maximal active features per patchis 128. In second reconstructed image 9512 the maximal active featuresper patch is 64. In third reconstructed image 9513 the maximal activefeatures per patch is 48. In fourth reconstructed image 9514 the maximalactive features per patch is 32. In fifth reconstructed image 9515 themaximal active features per patch is 16.

The following shows the reconstructed image based on its sparserepresentation of no more than 100,000 floating-point numbers, withvarious degrees of clipping. In agreement to the distribution of activefeatures (see previous histogram), high-fidelity reconstruction of theimage is possible as long as each patch can be represented by at least apredefined number (for example—16, 32, 48, 64 and 128) active features.The exact threshold varies depending on the content of the image, but isexpected to be lower in higher-dimensional representations.

The sparse representation illustrated above provides a viablealternative to convolutional neural network based object detection interms of low-level feature extraction, with the advantage that it workson unlabeled, limited training data, and enables backward visualization.

An object detection method that uses the spare representation mayinclude generating extract high-level, abstract features (for examplehigh level features that are comparable to those given by YOLO/MSSD) bytraining additional layers of dictionaries on top of the already sparsefeatures and taking into account more contextual information.

Similarity Pooling

The first layer of descriptors of an image was illustrated above andinclude assigning a sparse representation to each patch (for example of16 by 16 pixels).

The patches may then be grouped to groups of patches—wherein each groupmay be calculated based on a similarity between patches.

Thus, after generating a first sparse layer (sp0) the patches are pooledaccording to their similarity instead of using a fixed 3×3 grid.

Since the sparse feature vectors in this case are sparse, the similarity(denoted S(a,b)) between two patches (patch a and patch b) may becalculated by a normalized dot product of their respective vectors (forexample—even without mean subtraction):

${s\left( {a,b} \right)} = \frac{v_{a} \cdot v_{b}}{{v_{a}}{v_{b}}}$

S(a,b) is compared to a threshold and once exceed patches a and b aredeemed similar to each other.

In contrast to clustering in the higher layers, the similarity amongpatches that are located only within a certain radius(nearest-neighbors) are considered. Hence the computational complexityscales as O(n), where n is the number of patches, as opposed to O(n²) asin the case for all-to-all connectivity.

A fixed threshold is then applied to the resulting similarity.

Any connected subgraph is considered a single pooled patch for the nextlayer and is represented by an average feature vector.

FIG. 11 illustrates image 9521 that includes 1077 groups of patches (outof a total of 2560 patches per image), that were obtained using a poolradius of 1.5 patches and a similarity threshold of 0.5.

FIG. 11 illustrates that after the first layer of sparse decomposition,the features result in a low-level segmentation of the image.Homogeneous regions like road surface and sky are collected into singlegroups, whereas more complex objects remain fragmented.

FIG. 11 also illustrates original image 9522 and reconstructed image9523. Reconstructed image 9523 is reconstructed using the resultingaverage feature vector that represents each region (sm0→sp0→img), withslight loss of quality.

Lower thresholds result in more aggressive pooling, and less informationretention—as illustrated in images 9524, 9525 and 9526.

FIG. 12 illustrates image 9524 that includes 848 groups of patches (outof a total of 2560 patches per image), that were obtained using a poolradius of 1.5 patches and a similarity threshold of 0.3.

FIG. 12 also illustrates original image 9525 and reconstructed image9526. Reconstructed image 9526 is reconstructed using the resultingaverage feature vector that represents each region (sm0→sp0→img), withslight loss of quality.

FIG. 13 illustrates image 9527 that includes 600 groups of patches (outof a total of 2560 patches per image), that were obtained using a poolradius of 1.5 patches and a similarity threshold of 0.3.

FIG. 13 also illustrates image 9528 that includes 1107 groups of patches(out of a total of 2560 patches per image), that were obtained using apool radius of 1.5 patches and a similarity threshold of 0.3.

Configuring Spanning Elements

The analysis of content of a media unit may be executed by generating asignature of the media unit and by comparing the signature to referencesignatures. The reference signatures may be arranged in one or moreconcept structures or may be arranged in any other manner. Thesignatures may be used for object detection or for any other use.

The signature may be generated by creating a multidimensionalrepresentation of the media unit. The multidimensional representation ofthe media unit may have a very large number of dimensions. The highnumber of dimensions may guarantee that the multidimensionalrepresentation of different media units that include different objectsis sparse—and that object identifiers of different objects are distantfrom each other—thus improving the robustness of the signatures.

The generation of the signature is executed in an iterative manner thatincludes multiple iterations, each iteration may include an expansionoperations that is followed by a merge operation. The expansionoperation of an iteration is performed by spanning elements of thatiteration.

FIG. 14 illustrates a method 5000 for generating a signature of a mediaunit.

Method 5000 may start by step 5010 of receiving or generating sensedinformation.

The sensed information may be a media unit of multiple objects.

Step 5010 may be followed by processing the media unit by performingmultiple iterations, wherein at least some of the multiple iterationscomprises applying, by spanning elements of the iteration, dimensionexpansion process that are followed by a merge operation.

The processing may include:

-   -   Step 5020 of performing a k'th iteration expansion process (k        may be a variable that is used to track the number of        iterations).    -   Step 5030 of performing a k'th iteration merge process.    -   Step 5040 of changing the value of k.    -   Step 5050 of checking if all required iterations were done—if so        proceeding to step 5060 of completing the generation of the        signature. Else—jumping to step 5020.

The output of step 5020 is a k'th iteration expansion results 5120.

The output of step 5030 is a k'th iteration merge results 5130.

For each iteration (except the first iteration)—the merge result of theprevious iteration is an input to the current iteration expansionprocess.

The method may include a configuration step of configuring the spanningelements.

FIG. 15 is an example of a signature 6027 of a media unit that is animage 6000 and of an outcome 6013 of the last (K'th) iteration.

The image 6001 is virtually segments to segments 6000(i,k). The segmentsmay be of the same shape and size but this is not necessarily so.

Outcome 6013 may be a tensor that includes a vector of values per eachsegment of the media unit. One or more objects may appear in a certainsegment. For each object—an object identifier (of the signature) pointsto locations of significant values, within a certain vector associatedwith the certain segment.

For example—a top left segment (6001(1,1)) of the image may berepresented in the outcome 6013 by a vector V(1,1) 6017(1,1) that hasmultiple values. The number of values per vector may exceed 100, 200,500, 1000, and the like.

The significant values (for example—more than 10, 20, 30, 40 values,and/or more than 0.1%, 0.2%. 0.5%, 1%, 5% of all values of the vectorand the like) may be selected. The significant values may have thevalues—but may eb selected in any other manner.

FIG. 15 illustrates a set of significant responses 6015(1,1) of vectorV(1,1) 6017(1,1). The set includes five significant values (such asfirst significant value SV1(1,1) 6013(1,1,1), second significant valueSV2(1,1), third significant value SV3(1,1), fourth significant valueSV4(1,1), and fifth significant value SV5(1,1) 6013(1,1,5).

The image signature 6027 includes five indexes for the retrieval of thefive significant values—first till fifth identifiers ID1-ID5 are indexesfor retrieving the first till fifth significant values.

FIG. 16 illustrates various spanning elements 5061(1)-5061(3).

Each relevant spanning element may perform a spanning operation thatincludes assigning an output value that is indicative of an identity ofthe relevant spanning elements of the iteration. The output value mayalso be indicative of identities of previous relevant spanning elements(from previous iterations).

For example—assuming that spanning element number fifty is relevant andis associated with a unique set of values of eight and four—then theoutput value may reflect the numbers fifty, four and eight—for exampleone thousand multiplied by (fifty+forty) plus forty. Any other mappingfunction may be applied.

FIG. 16 also illustrates the steps executed by each spanning element:

-   -   Checking if the merge results are relevant to the spanning        element (step 5091).    -   If-so—completing the spanning operation (step 5093).    -   If not—entering an idle state (step 5092).

FIG. 17 illustrates an example of a clusters of a signatures matchingprocess.

It is assumed that there are multiple (M) cluster structures4974(1)-4974(M). Each cluster structure includes cluster signatures,metadata regarding the cluster signatures.

For example—first cluster structure 4974(1) includes multiple (N1)signatures (referred to as cluster signatures CS) CS(1,1)-CS(1,N1)4975(1,1)-4975(1,N1) and metadata 4976(1).

Yet for another example—M'th cluster structure 4974(M) includes multiple(N2) signatures (referred to as cluster signatures CS) CS(M,1)-CS(M,N2)4975(M,1)-4975(M,N2) and metadata 4976(M).

FIG. 17 also illustrates a media unit signature 4972 that is compared tothe signatures of the M cluster structures—from CS(1,1) 4975(1,1) tillCS(M,N2) 4975(M,N2).

We assume that one or more cluster structures are matching clusterstructures.

Once the matching cluster structures are found the method proceeds bygenerating shape information that is of higher accuracy then thecompressed shape information.

For example—assuming that the matching signatures include CS(1,1)2975(1,1), CS(2,5) 2975(2,5), CS(7,3) 2975(7,3) and CS(15,2) 2975(15,2).

The number of signatures per concept structure may change over time—forexample due to cluster reduction attempts during which a CS is removedfrom the structure to provide a reduced cluster structure, the reducedstructure structure is checked to determine that the reduced clustersignature may still identify objects that were associated with the(non-reduced) cluster signature—and if so the signature may be reducedfrom the cluster signature.

The signatures of each cluster structures are associated to each other,wherein the association may be based on similarity of signatures and/orbased on association between metadata of the signatures.

Assuming that each cluster structure is associated with a uniqueobject—then objects of a media unit may be identified by finding clusterstructures that are associated with said objects. The finding of thematching cluster structures may include comparing a signature of themedia unit to signatures of the cluster structures—and searching for oneor more matching signature out of the cluster signatures.

Each cluster may be identified by a cluster identifier. The clusteridentifier may differ by size (for example by number of objectidentifiers) than a signature. One or more cluster identifiers mayidentify the cluster. A cluster identifier may include identifiers thatare shared between CSs, may include identifiers that appear (even if notshared) in a CS, and the like. The cluster identifier may be generatedby applying any function on the CS of a cluster.

For example—assuming that a cluster identifier include identifiers thatare shared between two or more CS of the cluster. If no identifier isshared between all CS of the cluster—then multiple cluster identifiermay be required to represent a single cluster. The cluster identifiermay include all (or at least some) of the signature that appear in oneor more CSs.

FIG. 18 illustrates a method 9600 for configuring spanning elements of asignature generator.

Method 9600 may include the following steps:

-   -   Receiving test images 9602.    -   Generating, by applying a unsupervised dictionary learning        process, sparse signatures of the test images; wherein a sparse        signature of a test image comprises multiple vectors, each        vector represents a test image segment; wherein each vector        comprises more zero valued elements than non-zero valued        elements; wherein each element represent appearances, in the        test image segment, of a unique pattern associated with the        element 9604.    -   Calculating occurrence information regarding an occurrence of        the unique patterns in groups of test image segments 9606.    -   Selecting, based on the occurrence information, a set of        combinations of unique patterns 9608.    -   Associating different members of the set to different spanning        elements of the signature generator 9610.

The set of combinations may include most popular combinations of theunique patterns. The set may include a predefined number of most popularcombinations, all combinations of the unique patterns that exceed apopularity threshold. The rule for determining the size and/or thepopularity threshold may be fixed, or may change over time.

The method may include selecting the set of combinations based onpopularity of combinations of the unique patterns and based on adistance between the combinations of the unique patterns. Any costfunction may be selected for determining the set of combinations. Forexample—there may be applied a distance threshold or a distance range sothat only unique patterns within the range (or above or below thethreshold) may be elected—regardless of their popularity. Yet foranother example—there may be applied a popularity threshold or apopularity range so that only unique patterns within the range (or aboveor below the threshold) may be elected—regardless of their distance. Yetfor a further example—the selection may be based on a combination ofpopularity and distance.

The groups of test image segments may include test image segments thatare adjacent to each other.

The groups of test image segments may be of a same size.

The calculating of the occurrence information may be related to groupsof first size of test image segments; wherein the selecting may includeselecting a first set of combinations of unique patterns; and whereinthe associating may include associating different members of the firstset to different first spanning elements of the signature generator.

The method may further include calculating second occurrence informationregarding an occurrence of the unique patterns in second groups of testimage segments; the second groups are of a second size that exceeds thefirst size; selecting, based on the second occurrence information, asecond set of combinations of unique patterns; and associating differentmembers of the second set to different second spanning elements of thesignature generator. These steps may add a layer of representations thatmay be mapped to the first layer of representations and may for a cortexstructure. The number of layers may exceed two.

Each spanning element may be configured to determine whether it isrelevant to a signature generation process based on the uniquecombination of one or more object identifiers that are associated withthe spanning element. Thus—when a spanning element receives as input(for example as a result of a previous merge iteration) the uniquecombination (either alone or on addition to other signatures)—spanningelement is relevant and completes the expansion process. If a spanningelement does not receive (at least) the unique combination—the spanningelement does not output a expansion result.

FIG. 19 illustrates method 9420 of generating a signature of a sensedinformation unit.

Method 9420 may include the following steps:

-   -   Receiving or generating a sensed information unit 9422.    -   Calculating the signature of the sensed information unit by        performing multiple iterations, wherein each iteration of at        least some of the multiple iterations may include applying, by        spanning elements related to the iteration, a dimension        expansion process that may be followed by a merge operation.        9424

The spanning elements may be configured by executing method 9400.

Method 9420 may also include:

-   -   Finding at least one matching cluster, each matching cluster has        a cluster signature that matches the signature of the sensed        information 9426.    -   Determining that the sensed information unit includes at least        one object that is associated with the at least one matching        clusters 9428.

Method 9420 may be preceded by method 9600 of configuring the spanningelements utilized in step 9424.

FIG. 20 illustrates an example of a system capable of executing one ormore of the mentioned above methods.

The system include various components, elements and/or units.

A component element and/or unit may be a processing circuitry may beimplemented as a central processing unit (CPU), and/or one or more otherintegrated circuits such as application-specific integrated circuits(ASICs), field programmable gate arrays (FPGAs), full-custom integratedcircuits, etc., or a combination of such integrated circuits.

Alternatively, each component element and/or unit may implemented inhardware, firmware, or software that may be executed by a processingcircuitry.

System 4900 may include sensing unit 4902, communication unit 4904,input 4911, processor 4950, and output 4919. The communication unit 4904may include the input and/or the output.

Input and/or output may be any suitable communications component such asa network interface card, universal serial bus (USB) port, disk reader,modem or transceiver that may be operative to use protocols such as areknown in the art to communicate either directly, or indirectly, withother elements of the system.

Processor 4950 may include at least some out of

-   -   Multiple spanning elements 4951(q).    -   Multiple merge elements 4952(r).    -   Signature generator 4958.

While the foregoing written description of the invention enables one ofordinary skill to make and use what is considered presently to be thebest mode thereof, those of ordinary skill will understand andappreciate the existence of variations, combinations, and equivalents ofthe specific embodiment, method, and examples herein. The inventionshould therefore not be limited by the above described embodiment,method, and examples, but by all embodiments and methods within thescope and spirit of the invention as claimed.

In the foregoing specification, the invention has been described withreference to specific examples of embodiments of the invention. It will,however, be evident that various modifications and changes may be madetherein without departing from the broader spirit and scope of theinvention as set forth in the appended claims.

Moreover, the terms “front,” “back,” “top,” “bottom,” “over,” “under”and the like in the description and in the claims, if any, are used fordescriptive purposes and not necessarily for describing permanentrelative positions. It is understood that the terms so used areinterchangeable under appropriate circumstances such that theembodiments of the invention described herein are, for example, capableof operation in other orientations than those illustrated or otherwisedescribed herein.

Furthermore, the terms “assert” or “set” and “negate” (or “deassert” or“clear”) are used herein when referring to the rendering of a signal,status bit, or similar apparatus into its logically true or logicallyfalse state, respectively. If the logically true state is a logic levelone, the logically false state is a logic level zero. And if thelogically true state is a logic level zero, the logically false state isa logic level one.

Those skilled in the art will recognize that the boundaries betweenlogic blocks are merely illustrative and that alternative embodimentsmay merge logic blocks or circuit elements or impose an alternatedecomposition of functionality upon various logic blocks or circuitelements. Thus, it is to be understood that the architectures depictedherein are merely exemplary, and that in fact many other architecturesmay be implemented which achieve the same functionality.

Any arrangement of components to achieve the same functionality iseffectively “associated” such that the desired functionality isachieved. Hence, any two components herein combined to achieve aparticular functionality may be seen as “associated with” each othersuch that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. Likewise, any two components soassociated can also be viewed as being “operably connected,” or“operably coupled,” to each other to achieve the desired functionality.

Furthermore, those skilled in the art will recognize that boundariesbetween the above described operations merely illustrative. The multipleoperations may be combined into a single operation, a single operationmay be distributed in additional operations and operations may beexecuted at least partially overlapping in time. Moreover, alternativeembodiments may include multiple instances of a particular operation,and the order of operations may be altered in various other embodiments.

Also for example, in one embodiment, the illustrated examples may beimplemented as circuitry located on a single integrated circuit orwithin a same device. Alternatively, the examples may be implemented asany number of separate integrated circuits or separate devicesinterconnected with each other in a suitable manner.

However, other modifications, variations and alternatives are alsopossible. The specifications and drawings are, accordingly, to beregarded in an illustrative rather than in a restrictive sense.

In the claims, any reference signs placed between parentheses shall notbe construed as limiting the claim. The word ‘comprising’ does notexclude the presence of other elements or steps then those listed in aclaim. Furthermore, the terms “a” or “an,” as used herein, are definedas one or more than one. Also, the use of introductory phrases such as“at least one” and “one or more” in the claims should not be construedto imply that the introduction of another claim element by theindefinite articles “a” or “an” limits any particular claim containingsuch introduced claim element to inventions containing only one suchelement, even when the same claim includes the introductory phrases “oneor more” or “at least one” and indefinite articles such as “a” or “an.”The same holds true for the use of definite articles. Unless statedotherwise, terms such as “first” and “second” are used to arbitrarilydistinguish between the elements such terms describe. Thus, these termsare not necessarily intended to indicate temporal or otherprioritization of such elements. The mere fact that certain measures arerecited in mutually different claims does not indicate that acombination of these measures cannot be used to advantage.

While certain features of the invention have been illustrated anddescribed herein, many modifications, substitutions, changes, andequivalents will now occur to those of ordinary skill in the art. It is,therefore, to be understood that the appended claims are intended tocover all such modifications and changes as fall within the true spiritof the invention.

It is appreciated that various features of the embodiments of thedisclosure which are, for clarity, described in the contexts of separateembodiments may also be provided in combination in a single embodiment.Conversely, various features of the embodiments of the disclosure whichare, for brevity, described in the context of a single embodiment mayalso be provided separately or in any suitable sub-combination.

It will be appreciated by persons skilled in the art that theembodiments of the disclosure are not limited by what has beenparticularly shown and described hereinabove. Rather the scope of theembodiments of the disclosure is defined by the appended claims andequivalents thereof.

What is claimed is:
 1. A method for configuring spanning elements of asignature generator, the method comprises: receiving test images;generating, by applying a unsupervised dictionary learning process,sparse signatures of the test images; wherein a sparse signature of atest image comprises multiple vectors, each vector represents a testimage segment; wherein each vector comprises more zero valued elementsthan non-zero valued elements; wherein each element representappearances, in the test image segment, of a unique pattern associatedwith the element; calculating occurrence information regarding anoccurrence of the unique patterns in groups of test image segments;selecting, based on the occurrence information, a set of combinations ofunique patterns; and associating different members of the set todifferent spanning elements of the signature generator.
 2. The methodaccording to claim 1 wherein the set of combinations comprises mostpopular combinations of the unique patterns.
 3. The method according toclaim 1 comprising selecting the set of combinations based on popularityof combinations of the unique patterns and based on a distance betweenthe combinations of the unique patterns.
 4. The method according toclaim 1 wherein the groups of test image segments comprises test imagesegments that are adjacent to each other.
 5. The method according toclaim 1 wherein the groups of test image segments are of a same size. 6.The method according to claim 1 wherein the calculating of theoccurrence information is related to groups of first size of test imagesegments; wherein the selecting comprises selecting a first set ofcombinations of unique patterns; and wherein the associating comprisesassociating different members of the first set to different firstspanning elements of the signature generator.
 7. The method according toclaim 6 further comprising: calculating second occurrence informationregarding an occurrence of the unique patterns in second groups of testimage segments; the second groups are of a second size that exceeds thefirst size; selecting, based on the second occurrence information, asecond set of combinations of unique patterns; and associating differentmembers of the second set to different second spanning elements of thesignature generator.
 8. The method according to claim 1 wherein thefinding of the set of decorrelated elements is executed in an iterativemanner, one subset of decorrelated elements after the other.
 9. Themethod according to claim 1 wherein the finding of the set ofdecorrelated elements is executed in an iterative manner, onedecorrelated element after the other.
 10. The method according to claim1 wherein the representations of the test sensed information units aresignatures generated by the signature generator.
 11. The methodaccording to claim 1 wherein the representations of the test sensedinformation units differ from signatures generated by the signaturegenerator.
 12. The method according to claim 1 wherein the associatingcomprises gradually associating the different unique combinations to allspanning elements.
 13. The method according to claim 1 comprisingconfiguring the spanning elements based on a frequency of appearance ofpatterns in the test images.
 14. The method according to claim 1comprising assigning identifiers of a same object to a same spanningelement.
 15. The method according to claim 1 comprising searching forcandidate decorrelated elements in a random manner and finding, out ofcandidate decorrelated elements, the set of decorrelated elements. 16.The method according to claim 1 wherein each clusters of therepresentations is of at least a minimal predefined size and wherein anumber of clusters of the representations is limited to a maximalpredefined number.
 17. The method according to claim 1 the decorrelatedelements are the cluster identifiers and wherein the mapping comprisesmapping each decorrelated cluster identifier to set to a uniquecombination of one or more object identifiers, wherein at least oneunique combination differs from a signature by number of objectidentifiers.
 18. A method for generating a signature of a sensedinformation unit, the method comprises: receiving or generating a sensedinformation unit; and calculating the signature of the sensedinformation unit by performing multiple iterations, wherein eachiteration of at least some of the multiple iterations comprisesapplying, by spanning elements related to the iteration, a dimensionexpansion process that is followed by a merge operation; whereinspanning elements related to the multiple iterations are configured by:receiving test sensed information units; generating representations ofthe test sensed information units; wherein the representations areindicative of features of the test sensed information units; finding aset of decorrelated elements, wherein the decorrelated elements areselected out of (i) representations of the test sensed informationunits, and (ii) cluster identifiers that identify clusters of therepresentations of the test sensed information units; mapping eachdecorrelated element of the set to a unique combination of one or moreobject identifier; and associating different unique combinations to thespanning element of the signature generator.
 19. A non-transitorycomputer readable medium for configuring spanning elements of asignature generator, the non-transitory computer readable medium storesinstructions for: receiving test sensed information units; generatingrepresentations of the test sensed information units; wherein therepresentations are indicative of features of the test sensedinformation units; finding a set of decorrelated elements, wherein thedecorrelated elements are selected out of (i) representations of thetest sensed information units, and (ii) cluster identifiers thatidentify clusters of the representations of the test sensed informationunits; mapping each decorrelated element of the set to a uniquecombination of one or more object identifier; and associating differentunique combinations to the spanning element of the signature generator.20. The non-transitory computer readable medium according to claim 18wherein the finding of the set of decorrelated elements is executed inan iterative manner, one subset of decorrelated elements after theother.
 21. The non-transitory computer readable medium according toclaim 18 wherein the finding of the set of decorrelated elements isexecuted in an iterative manner, one decorrelated element after theother.
 22. The non-transitory computer readable medium according toclaim 18 wherein the representations of the test sensed informationunits are signatures generated by the signature generator.
 23. Thenon-transitory computer readable medium according to claim 18 whereinthe representations of the test sensed information units differ fromsignatures generated by the signature generator.
 24. The non-transitorycomputer readable medium according to claim 18 wherein the associatingcomprises gradually associating the different unique combinations to allspanning elements.
 25. The non-transitory computer readable mediumaccording to claim 18 that stores instructions for configuring thespanning elements based on a frequency of appearance of patterns in thetest images.
 26. The non-transitory computer readable medium accordingto claim 18 that stores instructions for assigning identifiers of a sameobject to a same spanning element.
 27. The non-transitory computerreadable medium according to claim 18 that stores instructions forsearching for candidate decorrelated elements in a random manner andfinding, out of candidate decorrelated elements, the set of decorrelatedelements.
 28. The non-transitory computer readable medium according toclaim 18 wherein each clusters of the representations is of at least aminimal predefined size and wherein a number of clusters of therepresentations is limited to a maximal predefined number.
 29. Thenon-transitory computer readable medium according to claim 18 whereinthe decorrelated elements are the cluster identifiers and wherein themapping comprises mapping each decorrelated cluster identifier to set toa unique combination of one or more object identifiers, wherein at leastone unique combination differs from a signature by number of objectidentifiers.